Handle type methodtables properly (#5)

For types, the .mt field is for Type; .ms is the constructor method list

Author: timholy

src/visit.jl

@@ -93,7 +93,7 @@ function _visit(@nospecialize(operation), @nospecialize(f::Callable), visited::I
     if operation(f)
         ml = methods(f)
         _visit(operation, ml.mt, visited, print)
-        Base.visit(ml.mt) do m
+        for m in ml.ms
             _visit(operation, m, visited, print)
         end
     end

test/runtests.jl

@@ -58,6 +58,12 @@ end
         true
     end
     @test nitems[] == 0
+
+    # Handle constructors properly
+    visit(IndexStyle) do m
+        isa(m, Method) && @test Base.unwrap_unionall(m.sig).parameters[1].parameters[1] === IndexStyle
+        return m === IndexStyle
+    end
 end
 
 @testset "Backedges" begin